The present invention relates to a head suspension for holding a head slider and a disk drive unit, and more precisely relates to a head slider which includes an anti-vibration structure for restricting transmission of vibration to the head slider, and a countermeasure to static electricity during manufacturing, and a disk drive unit including said head suspension.
In a disk drive unit, e.g., a hard disk drive unit, a magnetic optical disk drive unit, a head slider floats over a rotating disk. A head element, which is mounted on the head slider, writes data on or reads data from the disk. These days, to increase recording density of the disk, the floating level of the head slider is made lower and the size of the head element is made smaller. In the disk drive unit, it is important to restrict vibration of the head slider, which is held by a head suspension, so as to correctly position the head element. If the head slider is vibrated, control for positioning the head element is very difficult, a high speed operation of the head slider is obstructed and writing errors or reading errors are apt to occur, so that reliability of the disk drive unit must be lower.
A conventional head suspension is shown in FIGS. 1A and 1B. FIG. 1A is a plan view of the head suspension; FIG. 1B is a side view thereof.
A head suspension 13 has a gimbal 2, which has a front end on which a head slider 3 is mounted. A base end of the head slider 13 is attached to an arm (not shown) with a spacer 7. The arm is turned about a shaft so as to move the head slider 3 to an assigned position on the disk.
In the head suspension 13 shown in FIG. 1, vibrations which are generated in a voice coil motor (not shown) for driving the arm, and a spindle motor (not shown) for rotating the disk, are apt to be transmitted to the head slider 3. To restrict the transmission of the vibrations, an anti-vibration member 6 is adhered on a head suspension 14 as shown in FIG. 2. The anti-vibration member 6 is adhered on a face opposite to the face on which the head slider 3 is mounted. By adhering the anti-vibration member 6, the anti-vibration member 6 is vibrated by the vibration of the head suspension 14, so that vibration energy is converted into heat energy. By converting the vibration energy, the vibration transmitted to the head slider 3 can be restricted.
However, these days, a higher access speed of the disk drive unit is required. During the accessing action, the head slider is moved at high speed and a great acceleration is applied to the head suspension. As a result, the head suspension 14 is vibrated more. Thus, in spite of the anti-vibration member, the vibrations of the head slider cannot be ignored.
By covering not only the rigid section 4 but also the spring section 5 with the anti-vibration member 6, the vibration of the head slider can be restricted. But, by covering the spring section 5 with the anti-vibration member 6, a predetermined elastic pressure of the head suspension 14 is changed. The elastic pressure of the head suspension 14 influences the floating level of the head slider 3. If the elastic pressure is much greater than the predetermined value, the floating level of the head slider 3 is quite low so that the head slider 3 is apt to be crushed. On the other hand, if the elastic pressure is much less than the predetermined value, the floating level of the head slider 3 is quite high so that recorded data cannot be read correctly and reading errors are frequently caused. Therefore, the head suspension must keep the predetermined elastic pressure. Further, the head suspension must have an improved anti-vibration member so as to execute high speed operation. By improving the disadvantages of the conventional head suspension, a reliable disk drive unit can be realized.
The anti-vibration member 6 must be carefully adhered onto the head suspension 14 so as not to damage the head element of the head slider 3 by static electricity. The head element is a precise element, e.g., an MR element, a GMR element, so its resisting voltage is quite low, e.g., 5-20 [V].
The anti-vibration member 6 is usually adhered on a release paper. When the anti-vibration member 6 is to be adhered, it is peeled off from the release paper. When the anti-vibration member 6 is peeled off, static electricity of 200 or more is generated. Conventionally, the static electricity is neutralized by an ionizer, then the anti-vibration member 6 is adhered onto the head suspension 14. However, the static electricity cannot be fully neutralized, so the head elements are often damaged and the reliability of the disk drive units are made lower.
An object of the present invention is to provide a head suspension, which can be assembled without damaging the head element.
Another object of the present invention is to provide a reliable disk drive unit including the head suspension.
The head suspension of the present invention comprises: a rigid section for holding a head slider which writes data on and reads data from a disk, the rigid section being capable of bearing an external force whose direction is perpendicular to a recording face of the disk; a spring section having elasticity in the direction perpendicular to the recording face of the disk; and an anti-vibration member being provided in the spring section, the anti-vibration member partially having a vacant space. With this structure, area of the anti-vibration member covering the spring section can be correctly maintained, so that change of elastic pressure of the head suspension, which is caused by adhering the anti-vibration member, can be restricted. As a result, the change of the elastic pressure of the head suspension can be maintained within a proper range, vibration transmission to the head slider can be restricted, and the head slider can be floated stably.
In the head suspension, the anti-vibration member may cover the rigid section and the spring section and may have an opening or a slit in a part covering the spring section. With this structure, the area of the anti-vibration member covering the spring section is reduced, so that the head suspension never has excessive elastic pressure and the head slider can be stably floated, without loosing the effect of the anti-vibration member, which restricts the vibration of the head suspension.
In the head suspension, the anti-vibration member may be divided into a first anti-vibration member, which covers the rigid section, and a second anti-vibration member, which covers the spring section, with a separation. By dividing the anti-vibration member, areas covered with the first and second anti-vibration members are separated. As a result, in comparison with the head suspension in which the anti-vibration member covers the rigid section and the spring section, the head suspension having less elastic pressure can be realized, and the head slider can be stably floated without losing the effect of the anti-vibration member, which restricts the vibration of the head suspension.
In the head suspension the second anti-vibration member may be located on a border between the spring section and a spacer of a base end of the head suspension. With this structure, both of the anti-vibration member and the spacer restrict the vibration. Further, the change of the elastic pressure of the head suspension can be restricted to a minimum because the area of the spring section covered with the anti-vibration member is small.
The disk drive unit of the present invention includes the head suspension of the present invention. By employing said head suspension, the disk drive unit can be reliably operated at high speed because the head suspension maintains the proper elastic pressure and the vibration of the head slider can be effectively restricted.
Another head suspension of the present invention comprises: a base member; an anti-vibration member for restricting vibration of a head slider, the anti-vibration member being provided on the base member; and an electric conductive layer being formed on the anti-vibration member. By the electric conductive layer on the anti-vibration member, charging static electricity in the anti-vibration member can be prevented and the head element of the head slider of the head suspension is never damaged by the static electricity.
The disk drive unit including this head suspension can have high reliability.